Quasi-experimental Design

Summary

This video script introduces quasi-experimental design, a non-random assignment study aimed at estimating the causal impact of interventions. It highlights the design's resemblance to true experiments but without random participant selection. The script outlines different types, including non-equivalent comparison groups, pretest-posttest, interrupted time series, and combination designs, using examples like teaching methods and class hours to illustrate their application in determining the effectiveness of interventions.

Takeaways

• 🔬 Quasi-experimental design is an evidence-based interventional study that uses non-random assignment to estimate the causal impact of an intervention.
• 📊 It aims to determine causal relationships among variables, similar to true experimental research but without random selection of participants.
• 📝 The design includes pre-tests and post-tests, with the control group being optional depending on the design specifics.
• 🎓 The main objective is to evaluate the effectiveness of a treatment or intervention on a target population.
• 👥 The non-equivalent comparison groups design involves two testing groups that are not randomly assigned, leading to potential internal threats to validity.
• 🎼 An example study assesses the effectiveness of a new teaching method for music theory in bachelor of cultural and arts education students.
• 📉 The pretest and posttest design tests the dependent variable before and after the intervention, identifying changes as a result of the treatment.
• 👨‍🎓 This design is applied to students with low cognitive levels in music theory, using a pre-test to identify participants and a post-test to measure intervention effectiveness.
• 📈 The interrupted time series design involves multiple tests before and after an intervention, allowing for the observation of consistency and effectiveness over time.
• 🕒 An example of this design is determining the effect of shortened class hours on student productivity, with observations before and after the intervention.
• 🔄 The combination design merges elements of non-equivalent and pretest-posttest designs, comparing improvements between a test group receiving treatment and a control group.
• 🎼 Another study example explores the effects of a new teaching method on students' attitudes towards music theory, using pre- and post-tests to measure changes.

Q & A

What is a quasi-experimental design?

A quasi-experimental design is an evidence-based interventional study that uses non-random assignment to estimate the causal impact of an intervention on a target population, aiming to determine causal relationships among variables.

How does quasi-experimental design differ from true experimental research?

Quasi-experimental design resembles true experimental research but differs in that there is no random selection of participants involved in the study.

What are the key components of quasi-experimental design?

Quasi-experimental design involves pre-tests and post-tests and may or may not include a control group, depending on the design.

What is the main objective of quasi-experimental design?

The main objective of quasi-experimental design is to evaluate the effectiveness of a treatment or an intervention.

What is the non-equivalent comparison groups design in quasi-experimental research?

The non-equivalent comparison groups design involves two testing groups that are not randomly assigned, which may lead to internal threats to the validity of the research results.

What factors might influence the results of a non-equivalent comparison groups design?

Factors such as the student's IQ level, student behavior, teaching strategy, and student environment might influence the results of a non-equivalent comparison groups design.

What is the pretest and posttest design in quasi-experimental research?

The pretest and posttest design tests the dependent variable before and after the intervention is given, allowing researchers to observe changes due to the intervention.

How does the interrupted time series design differ from the pretest and posttest design?

The interrupted time series design involves a series of tests at given intervals before and after an intervention, allowing researchers to observe the consistency of the test and verify the effectiveness of the treatment.

What is a combination design in quasi-experimental research?

A combination design combines elements of non-equivalent designs and pretest and posttest designs, involving a test group and a control group, with only the test group receiving the intervention.

What is the purpose of using both a test group and a control group in a combination design?

The purpose is to determine the extent of improvement between the test group and control group and to assess whether changes are caused by the treatment or other factors.

Can you provide an example of a quasi-experimental design study mentioned in the script?

An example given in the script is a study assessing the effectiveness of a new method of teaching music theory to Bachelor of Cultural and Arts Education students.